MIS

ASSIGNMENT

TELECOMMUNICATION NETWORKS

INTRODUCTION:

A computer network or data network is a telecommunication network which allows computers to exchange data. In computer networks, networked computing devices exchange data with each other along network links (data connections). The connections between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.

Network computer devices that originate, route and terminate the data are called network nodes. Nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices can be said to be networked together when one device is able to exchange information with the other device, whether or not they have a direct connection to each other.

Computer networks differ in the transmission media used to carry their signals, the communications protocols to organize network traffic, the network's size, topology and organizational intent. In most cases, communications protocols are layered on (i.e. work using) other more specific or more general communications protocols, except for the physical layer that directly deals with the transmission media.

Computer networks support applications such as access to the World Wide Web, shared use of application and storage servers, printers, and fax machines, and use of email and instant messaging applications.

A telecommunications network is a collection of terminal nodes, links are connected so as to enable telecommunication between the terminals.

The transmission links connect the nodes together. The nodes use circuit switching, message switching or packet switching to pass the signal through the correct links and nodes to reach the correct destination terminal.

Each terminal in the network usually has a unique address so messages or connections can be routed to the correct recipients. The collection of addresses in the network is called the address space.

Examples of telecommunications networks are:

·         computer networks

·         the Internet

·         the telephone network

·         the global Telex network

·         the aeronautical ACARS network

LOCAL AREA NETWORK (LAN)

A local area network (LAN) is a computer network within a small geographical area such as a home, school, computer laboratory, office building or group of buildings.

DEFINITION:

A LAN is composed of inter-connected workstations and personal computers which are each capable of accessing and sharing data and devices, such as printers, scanners and data storage devices, anywhere on the LAN. LANs are characterized by higher communication and data transfer rates and the lack of any need for leased communication lines.

Many LANs are based partly or wholly on wireless technologies. Smartphones, tablet computers and laptops typically have wireless networking support built-in. In a wireless local area network, users may move unrestricted in the coverage area. Wireless networks have become popular in residences and small businesses, because of their ease of installation. Guests are often offered Internet access via a hotspot service.

LANs can maintain connections with other LANs via leased lines, leased services, or the Internet using virtual private network technologies. Depending on how the connections are established and secured in a LAN, and the distance involved, a LAN may also be classified as a metropolitan area network (MAN) or a wide area network (WAN).

A local area network, or LAN, consists of a computer network at a single site, typically an individual office building. A LAN is very useful for sharing resources, such as data storage and printers. LANs can be built with relatively inexpensive hardware, such as hubs, network adapters and Ethernet cables.

The smallest LAN may only use two computers, while larger LANs can accommodate thousands of computers. A LAN typically relies mostly on wired connections for increased speed and security, but wireless connections can also be part of a LAN. High speed and relatively low cost are the defining characteristics of LANs.

LANs are typically used for single sites where people need to share resources among themselves but not with the rest of the outside world. Think of an office building where everybody should be able to access files on a central server or be able to print a document to one or more central printers. Those tasks should be easy for everybody working in the same office, but you would not want somebody just walking outside to be able to send a document to the printer from their cell phone! If a local area network, or LAN, is entirely wireless, it is referred to as a wireless local area network, or WLAN.

WIDE AREA NETWORK (WAN)

A wide area network (WAN) is a telecommunications network or computer network that extends over a large geographical distance. Wide area networks often are established with leased telecommunication circuits.

Business, education and government entities use wide area networks to relay data among staff, students, clients, buyers, and suppliers from various geographical locations. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. The Internet may be considered a WAN.

A wide area network (WAN) is a computer network that spans a relatively large geographical area and consists of two or more interconnected local area networks (LANs).

A LAN is a network that connects computers and other devices in a relatively small area, typically a single building or a group of adjacent buildings.

Many WANs are built for one particular organization and are private. They are commonly implemented in enterprise networking environments to link offices in different cities, states, countries and even continents. WANs are also built by Internet service providers (ISPs) to provide connections from the LANs of their customers to the Internet. The Internet, which is a world-wide network of interconnected computer networks, is a WAN, and thus it is the largest WAN in existence.

WANs are commonly constructed using leased lines (i.e., dedicated telephone connections between two points that are set up for a company or other organization by a telecommunications common carrier), but they can also use conventional telephone lines and satellite links. At each end of the leased line a router connects to the LAN on one side and to a hub within the WAN on the other. A router is an electronic device and/or software that connects at least two networks and forwards packets (i.e., the fundamental unit of information transport in all modern computer networks) among them based on their IP addresses, network conditions, etc. A hub is a common connection point for multiple twisted pair copper wire cables or optical fiber cables in a LAN.

The term Wide Area Network (WAN) usually refers to a network which covers a large geographical area, and use communications circuits to connect the intermediate nodes. A major factor impacting WAN design and performance is a requirement that they lease communications circuits from telephone companies or other communications carriers. Transmission rates are typically 2 Mbps, 34 Mbps, 45 Mbps, 155 Mbps, 625 Mbps (or sometimes considerably more). 

Numerous WANs have been constructed, including public packet networks, large corporate networks, military networks, banking networks, stock brokerage networks, and airline reservation networks. Some WANs are very extensive, spanning the globe, but most do not provide true global coverage. Organizations supporting WANs using the Internet Protocol are known as Network Service Providers (NSPs). These form the core of the Internet. 

By connecting the NSP WANs together using links at Internet Packet Interchanges (sometimes called "peering points") a global communication infrastructure is formed. NSPs do not generally handle individual customer accounts (except for the major corporate customers), but instead deal with intermediate organizations whom they can charge for high capacity communications. They generally have an agreement to exchange certain volumes of data at a certain "quality of service" with other NSPs. So practically any NSP can reach any other NSP, but may require the use of one or more other NSP networks to reach the required destination. NSPs vary in terms of the transit delay, transmission rate, and connectivity offered.

METROPOLITAN AREA NETWORK (MAN)

A metropolitan area network (MAN) is a computer network larger than a local area network, covering an area of a few city blocks to the area of an entire city, possibly also including the surrounding areas.

A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN). The term is applied to the interconnection of networks in a city into a single larger network (which may then also offer efficient connection to a wide area network). It is also used to mean the interconnection of several local area networks by bridging them with back bone lines. The latter usage is also sometimes referred to as a campus network.

Examples of metropolitan area networks of various sizes can be found in the metropolitan areas of London, England; Lodz, Poland; and Geneva, Switzerland. Large universities also sometimes use the term to describe their networks. A recent trend is the installation of wireless MANs.

A Metropolitan Area Network (MAN) is one of a number of types of networks (see also LAN and WAN). A MAN is a relatively new class of network, it serves a role similar to an ISP, but for corporate users with large LANs. There are three important features which discriminate MANs from LANs or WANs:

1.             The network size falls intermediate between LANs and WANs. A MAN typically covers an area of between 5 and 50 km diameter. Many MANs cover an area the size of a city, although in some cases MANs may be as small as a group of buildings or as large as the North of Scotland.

2.             A MAN (like a WAN) is not generally owned by a single organisation. The MAN, its communications links and equipment are generally owned by either a consortium of users or by a single network provider who sells the service to the users. This level of service provided to each user must therefore be negotiated with the MAN operator, and some performance guarantees are normally specified.

3.             A MAN often acts as a high speed network to allow sharing of regional resources (similar to a large LAN). It is also frequently used to provide a shared connection to other networks using a link to a WAN.

A metropolitan area network, or MAN, consists of a computer network across an entire city, college campus or small region. A MAN is larger than a LAN, which is typically limited to a single building or site. Depending on the configuration, this type of network can cover an area from several miles to tens of miles. A MAN is often used to connect several LANs together to form a bigger network. When this type of network is specifically designed for a college campus, it is sometimes referred to as a campus area network, or CAN.

A Metropolitan Area Network (MAN) is a large computer network on the large geographical area that include several buildings or even the entire city (metropolis). The geographical area of the MAN is larger than LAN, but smaller than WAN. MAN includes many communicating devices and provides the Internet connectivity for the LANs in the metropolitan area.

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